Process for removing liquid residues from tanks and pipe systems



y 1929' J. MULDER ET AL 1,713,911

PROCESS FOR REMOVING LIQUID RESIDUES FROM TANKS AND PIPE SYSTEMS Filed NOV. 25 1926 2 Sheets-Sheet 1 y 21, 1929- J. MULDER ET AL PROCESS FOR REMOVING LIQUID RESIDUES FROM TANKS AND PIPE SYSTEMS Filed Nov. 23, 1926 2 Sheets-Sheet 2 F'lCarPJ Patented May 21, 1929.

EJITED STATES JAKOB MUILDER AND DIRK Parent QFFICE.

CHRISTIAAN ENDERT, 53., F BOTTERDAM, NETHEBLANDfii.

FROCESS FOR REMOVING LIQUID RESIDUES FROM TANKS AND PIPE SYSTEMS.

Application filed November 23, 1926, Serial Nov 150,363, and in Germany November 23, 1925.

This invention refers to a process for removing liquid residues from tanks and the pipe systems of the same, particularly in ships for the transport of liquid oil and the like such as petroleum and benzine.

In most tank ships for carrying oils and the like, it often occurs that after the liquid has been removed from the tanks by pumps, owing to the slightly slanting position of the ship, the suction mouth of the suction pipe becomes obstructed by the residues of the liquid left behind.

There are but few tank ships which are so well equipped that these final oil or benzine residues can be removed by means of the pumps. It is, therefore, necessary in such cases to wait until these benzine residues have been vaporized or else the liquid must be removed by means of buckets. In either case the process is laborious and in the latter case even dangerous.

The object of the invention is to make it possible to remove from the tanks by meansof an ejector applied according to this invention, not only the gases, but also the liquid residues.

By using the ejector, it is undesirable, so as to prevent any damage to the tanks, to apply a higher vacuum than that equal to a water column of a few meters. By the new process it is even possible, with the aid of a very low vacuum to also remove the liquid residues from the tanks.

In applying the new process it is possible, under the conditions described, to rapidly remove the liquid residues without it being necessary to open the closing cover of the tanks. For that purpose, according to this invention, the liquid is first sucked up with the aid of the ejector to a certain height in the suction pipe. Then by suddenly admitting steam pressure into the suction pipe, the liquid is forcibly driven out of the suction pipe and immediately after the ejector is again put in operation, then, owing to the great speed with which the air flows in, a whirling motion is set up around the suction mouth in consequence of which a froth, i. e., amixture of liquid and air is formed, which is carried away through the ejector. In most cases, for instance, if the process is applied in harbours, it will be im possible to eject the sucked up liquid in this manner into the open. This would be too dangerous and it will be generally necessary for the benzine to be gasified and neutralized by steam.

According to this invention, the mixture of liquid and air sucked up in the manner above described can be removed by the ejector into a special container in which the steam separates from the liquid and the liquid is left behind.

If the liquid collected in the container is to be gasified and neutralized by the steam, then, according to this invention, it can be brought back into the suction pipe through a pipe which connects the container with the suction pipe during the-suction process (when the connection between ejector and container is interrupted) through a specially devised arrangement for the purpose in a finely divided condition and conducted into the open with the gas sucked up from the principal tank through the ejector.

The invention is illustrated by way of example in the accompanying drawing.

Fig. 1 shows the complete arrangement for performing the method according to the invention.

Fig. 2 shows the said arrangement on a smaller scale fitted on a tank ship.

Figs. 3, 4: and 5 are similar longitudinal sections through the control valve, and illustrating the several operative positions thereof.

In the arrangement illustrated in the drawing, 1 is the ejector, 2 is the suction pipe, which ends at a short distance above the bottom 3 of the ship-tank and is fitted with a suction mouthpiece 4-. The pipe for the admission of the steam is indicated by 5, whilst 6 is the discharge outlet.

Betweenthe nozzle of the ejector and the discharge outlet 6 there is arranged a cook or rotary valve 7. By means of the said cook the following connections can be established.

a. A free outflow of the steam coming from the ejector and of the gases into the outer atmosphere.

6. Complete closing of the steam outlet in which case, by the admission of steam into the eject-or, the suction pipe 2 is brought under steam pressure.

0. The steam coming from the ejector and the liquid carried away is directed downwards in the cock 7 and discharged into a special container or liquid separator 8 which will be referred to later and in which the let.

liquid remains, Whilst the gases escape through the outlet pipe 9;

Now, if, in, a tank, the suction pipe is immersed inthe liquid residue and it is-there-v fore impossible to free the said tank from inflammable gases, according to the present invention,'the following procedure is adopt- The cock or rotary valve 7 is turnedrapid- '1. throu h the three successive ositions the latter spreads on the slanting bottom of the tank.

Position 0. Where the steam can again flow out of the ejector, but where it is led away downwards intothe special container 8.

v The froth formed at the inlet of the suction pipe 2 by passing steam into the tank through thesuction pipe (position b of valve 7) is lifted and discharged through the ejector when the latter is again rendered o erative by a suitable adjustment of valve This rapid reversal of pressure in pipe 2 will establish a powerful upward current of air and gas before the froth or air, gasand liquid mixture is disintegrated; This air and gas current will pick up large quantities of liquid as the latter tends to flow back into the spacepreviously occupied by the froth,

and will, when the head of liquid over the suction pipe inlet is not too great, continu ously break through the liquid seal which the residues tendv to establish over the suction pipe inlet. hen the liquid head is sufiicient to reestablish the liquid seal, it will be necessary to repeat'the above-described steps of forming a froth by blowing steam through the inlet pipe and then operating the ejector before the froth disintegrates to form a liquid seal over the suction pipe in- The rush of air and gas into the suction pipe inlet will give the liquid a whirlin'g motion about the mouthpiece or inlet 4, and this whirlingmotion, combined with the intermittent but practically continuous rush of air and gas through portions of the liquid tends to maintain the liquid adjacent the in let st in an agitated or frothy condition which facilitates its removal byfthe air and gas current.

In removing the residues of inflammable liquids, the fire hazard may be reducedor eliminated by discharging the material invapor phase and admixed with a relatively large volume of steam. The Valve 7 which controls the operation of the ejector system is preferably adapted to direct the discharge from the ejector either-to the atmosphere or to the container or liquid separator 8. Air,

steam and vapors pass from the separator 8 to the atmosphere through outlet pipe 9 while the liquid is trapped in the bottom of the separator.

These liquid residues sucked upfrom the 7 bottom of the tank are usually of little value and are of small commercial importance.

In most cases it will, therefore, be preferred to gasify those residues with the others. 'According to this invention, this can be efl ected by bringing back during the suc- I tion of the gases, through the ejector into the suction pipe, the liquid in the container 8 through an atomizerQi, provided in the pipe 10 (which pipe connects the container 8 with thesuction pipe 2) and conveying it into the atmosphere with the gases sucked up fromthe main tank.

The cock or rotary valve which serves to produce theaforesaid connection between the suction pipe Qand the container 8 or the outlet pipe 6 is'represented on a larger scale in FigsJB, 4t and The casing of this cock is indicated by 7, whilst 11 is the actual plug of the cook, the upper extension of which 12, by means of a stuifing box 13 is carried through the outer wall 7 and connected with a hand lever 1a, with which the rotary plugor cook 11 is brought to the dif ferent positions. For securing the correct position, the lever 14 is provided with a lock ing pin 16'provided with a head 17 and a spring 15. The other end of said pin '16 engages corresponding holes or depressions 18 in the body 7 of the rotary valve, so that the correct position is secured in the diifer ent working stages. The valve casing 7 is provided with flanges 19 for connecting the same between the ejector l and the discharge outlets 6. The three sectional views illustrate the valve casing in the same relative position as in Figs. 1 and 2, i. e., with the ejector arranged at the left'of the valve.

-Position a of the valve is illustrated in Figs.

therefrom and form a froth at the suction mouthpiece 4. The valve is then returned to the initial position to reduce'the pressure within pipe 2. A mixture of liquid and gases will be lifted by the suction and discharged from outlet Gas indicated in Fig. 1.

When the valve isturnecl into the position shown in Fig. 5, the steam, liquid and gases leaving the ejector 1 are diverted downwardly by the curved wall 20 of the valve, and discharged through outlet 21 of the valve into the liquid separator or trap 8. The liquid is retained within the trap or is returned to the suction pipe 2, while the gases and vapors pass out through outlet pipe 9, as shown in Fig. 2.

Let it be observed that the pipe 10 between the container 8 and the suction pipe 2 which contains the atomizer 2scan be suitably provided with a stop cock 23. The container 8 can also be arranged laterally in relation to the ejector and this arrangement may be adopted Without departing from the fundamental idea.

It will be apparent that other gases or vapors may be used in place of steam for operating the ejector, and that the term steam is used in the following claims in a descriptive and not a limiting sense.

The apparatus herein disclosedis claimed in our copending application #150,362 filed of even date herewith.

Vhat we claim is:

1. The method of removing liquid residues from tanks and the like by means of an ejector having a suction pipe, which method comprises forming a froth of the liquid at the inlet to suction pipe, and ejecting said liquid residues in the form of a froth.

2. The method of removing liquid residues from tanks and the like by means of a steam ejector having a suction pipe leading into said tank, which comprises forming a froth of the liquid residues, ejecting the froth from the tank through said pipe and ejector, passing the froth and steam into a liquid separator, and discharging the steam, air and vapors from said separator.

3. In the process of removing liquid resi dues from tanks and the like by means of a steam ejector and a suction pipe extending into said tank, the steps which comp-rise delivering steam through said suction pipe to form a froth at the inlet of said suction pipe, and then actuating said-ejector to reduce the pressure Within said suction pipe, whereby the liquid residues are lifted and ejected as a froth and under a relatively low reduction in pressure.

4. A process for removing liquid residues from tanks and the like by means of a steam ejector having a suction pipe leading into 5. A process as set forth in claim 4, Where-,

in the steam and froth are passed from the ejector into a liquid separator, and the separated liquid is returned to the suction pipe.

6. In a process for removing liquid residues from tanks and the like by means of a steam ejector having a suction pipe leading into said tank, the steps which comprise forming a froth of the liquid at the inlet to said suction pipe, lifting the froth through said pipe and ejector, passing the froth and steam into a liquid separator, discharging the gaseous components from said separator, and returning the separated liquid to said suction pipe in finely divided form.

In testimony whereof, We afiix our signatures.

' JAKOB MULDER.

DIRK CHRISTIAAN ENDERT, Junior. 

